U.S. Pat. Nos. 3,959,974, 4,301,655 and 4,417,447 issued to L. B. Thomas, disclose several embodiments of a combination internal combustion-steam engine, the power of which is increased and the efficiency of which is improved by cyclicly injecting water through the cylinder head into the combustion space above the piston when the power cylinder is sufficiently hot to produce superheated steam. While all three of the patented engine structures achieve the enumerated objectives, the improvement herein includes an engine structure which will more completely exhaust all of the combustion gases and improve the power characteristics of a gasoline or diesel engine. Furthermore, these patents represent improvements in two-cycle engines and the water injection concept can be improved by using a four-cycle principle and utilizing two companion cylinders to complete the four-cycle operation.
Accordingly, it is an object of this invention to provide a water-injection internal combustion engine which can be built to operate on either the Diesel principle of compression ignition or the Otto principle of low compression using a carburetor or fuel injection and spark ignition. Either technique will produce the heat needed by internal combustion for generating the superheated steam according to the invention.
Another object of this invention is to provide a new and improved water injection, internal combustion engine of the four-cycle design, which engine is characterized by sets of at least two companion cylinders separated by at least one transfer valve, one of which cylinders initiates combustion, wherein the burning gases are forced through the transfer valve into the second power cylinder where water is injected and the power and exhaust strokes are completed.
Another objecte of the invention is to provide a four-cycle, water-injection, internal combustion engine of either the compression ignition or spark ignition design, which engine is characterized by at least two companion cylinders having ceramic liners at the upper ends thereof and cooperating pistons with upper ceramic surfaces for reciprocation in the cylinders, respectively, with a pair of transfer valves located between the cylinders.
Yet another object of this invention is to provide a four-cycle, water-injection engine which can be adapted for compression ignition or spark ignition operation, which engine includes at least one pair of companion compression and power cylinders served by ceramic pistons, each of the cylinders having a conventional lower portion and a ceramic upper portion for operation at high temperatures, with a pair of transfer valves located between and communicating with the compression and power cylinders, wherein a fuel and air mixture is first compressed and burned in the compression cylinder and is then routed through the transfer valves to the power cylinder, where steam is generated to enhance the power cycle.